Arc-light electrode.



illuminating ingredients the present inventlon enone EGLY, 0E TREPTOW, NEAR SIEMENS &

BERLIN, GERMANY, 00., 0F LICHTENZBERG, NEAR BERLIN, GERMANY.

ASSIGNOR TO GEZBRUEDER ARC-LIGHT ELECTRODE.

'No Drawing. Application filed A ril 22,

To all whom it may concern:

Be it known that I, GEORG EGLY, a.sub]ect of the German Emperor, and residing at Treptow, near Berlin, Germany, have invented certain new and useful Improvements in Arc-Light Electrodes, of which the following is a specification.

My invention relates to are llght electrodesin general, and more partlcularlyto arc light'electrodes of that type In whlch illuminating admixtures or ingredients are employed in conjunction with carbon.

The primary object of the inventlon 1s to provide improved electrodes of this character containing illuminating ingredlents which emit a great light.

According to my invention I employ as for are light electrodes a chemical compound, or a mixture of one or more oxids of metals of the rare earths, (which group for the purposes of comprises particularly cerium, lanthanum and didymium) and one or more oxids of the alkaline earth metals (which group for the purposes of the invention includes particularly calcium, barium and strontium). I find that this special compound when present in arc lamp electrodes results in an exceptionally quietly burning light of great power and excellent color. Among the compounds of the substances mentioned above I may refer especially to a chemical compound of calcium oxid and cerium peroxid, which may be termed calcium ceriate. This compound may be formed by utilizing ordinary and well known chemical principles, as by heating the two substances together to redness.

Instead of employing the oxids of the rare earth and alkaline earth groups directly, salts or compounds may be employed, which when heated to incandescence form the oxids, as for example oxalates, carbonates, and so no.

An additional feature of my invention resides in the discovery that a peculiar improvement is obtained by adding a small quantity of fluorid and especially fluor-spar to the substances above mentioned. In the first place the color of the light is improved and in the second place the formation of slag is favorably influenced. Although fluor-spar might ordinarily impart to the light a disagreeable yellow color, I find that Specification of Letters Patent.

Patented Feb. 1, 1916.

1910. Serial No. 556,967.

in the present instance when used in conjunction with the substances referred to it renders the light pure white, and whereas fluor-spar might ordinarily cause great formatlon of slag, in the present combination I find that it hinders the formation of slag or completely does away with it. In order to obtain these effects, I find that a quantity of fluor-spar approximately 1 to 2% of the total mass of the electrode will suffice, but the pure white color of the light is still maintained when 10% of fluor-spar is added. A very suitable light emitting ingredient, for example, is one composed of one part calcium oxid, one part fluor-spar and three parts cerium peroxid.

The entire composition of the electrode may be represented according to my invention as follows: In the case of an electrode comprising a core and a mantle in which the weight of the mantle is approximately equal to the weight of the core, the entire electrode would comprise, for example, two to four parts calcium oxid, one to five parts fluor-sp ar, six to twelve parts cerium oxid or a mixture of oxids of the rare earths, the usual addition of one to five parts alkali and 74 to 90 parts of carbon. For this example five parts fluor-spar is the highest limit. As one may form the mantle of various thicknesses or entirely omit the mantle, the composition of a homogeneous carbon may be substantially as follows: four to eight parts calcium oxid, twelve to twenty-four parts cerium oxid or a mixture of the oxids of the rare earths, two to ten parts fiuor-spar, two to ten parts alkali, 52 to 80 parts of carbon. In this example it will be seen that ten parts of fiuor-spar will be the upper limit.

In addition to the efiect upon the formation of slag I find that the admixture of the substances in accordance with my present invention results in a considerable increase in light, which can not be obtained by employing the individual substances alone or by employing the fiuor-spar in combination with the rare earth oxid or alkaline earth alone. The admixture of fluor-spar in small quantities according to my present invention has the further advantage that the spluttering of the are light which occurs sometimes when the oxid combination alone is employed, is very much diminished or completely avoided.

I claim- 1. An arc light electrode having as illuminating ingredient calcium oxid and rare earth oxid of the cerium, lanthanum and didymium group.

2. An arc 1i ht electrode having as illuminating in re ient calcium oxid and rare earth oxi of the cerium, lanthanum and didymium group, and a flourid.

3. An arc light electrode having an illuminating ingredient consisting substantially of three parts cerium peroxid, one part calcium oxid, and one part fluor-spar.

4. An are light electrode having an illuminating ingredient comprising a compound of an oxid of cerium and calcium oxid.

have signed my in the presence of GEORG EGLY.

Witnesses HENRY HASPER, WOLDEMAR HAUPT. 

